Cassius Quests

Ok so in another post I already said that I don't quite get Cassius. However I know he's a good support and I often see him recommended when I look up teams for Yuki or Chizuru. Since I don't have much to go off of tho, I usually try to somewhat stick to guides combined with the knowledge I gained over some chars (which in Cass case isn't that much yet).

Game8 (a site where I'm a little uncertain how well those builds are since in the very beginning they recommended some really questionable stuff e.g. copying Cass Popeyes and stuff like that) recommended Chizuru with Rei and Cass. I use Rei and Chizuru anyways so I wanted to give him another shot.

The site I think kinda says sth along the lines of you're supposed to get the epiphany where you can chose one of the quests and go for Triple0. The card that creates is a dmg card which confuses me since his dmg is insanely low cuz...well he's a support.
Also the resulting quest card in turn doesnt feed into this quest. The only thing that actually makes sense to me is the epiphany of one of his other cards which generates a random quest card on quest completition.
And with shizurus cost reduction, getting the 0 quest done is admitedly fairly easy.

But I still don't quite get his loop. Why not for example go for the 1/1/1 quest? or why not pick his Fullhouse/Straight quest? Bc those cards are obviously 10x more usefull than the Triple0 Card.

I know there is some Setups where his Triple0 does more dmg and what not but I specifically mean his general use/loop and the setup with Chizuru mentioned on Game8
( https://game8.co/games/Chaos-Zero-Nightmare/archives/569513 ).